/**
 * @Question.Title: 二叉搜索树的范围和
 * @Question.No: 938
 * @Author: Dang Qi
 * @Date: 2021-04-27 11:07:06
 * @Description: 
 */
//给定二叉搜索树的根结点 root，返回值位于范围 [low, high] 之间的所有结点的值的和。 
//
// 
//
// 示例 1： 
//
// 
//输入：root = [10,5,15,3,7,null,18], low = 7, high = 15
//输出：32
// 
//
// 示例 2： 
//
// 
//输入：root = [10,5,15,3,7,13,18,1,null,6], low = 6, high = 10
//输出：23
// 
//
// 
//
// 提示： 
//
// 
// 树中节点数目在范围 [1, 2 * 104] 内 
// 1 <= Node.val <= 105 
// 1 <= low <= high <= 105 
// 所有 Node.val 互不相同 
// 
// Related Topics 树 深度优先搜索 递归 
// 👍 191 👎 0

package dq.leetcode.editor.cn;

import com.dq.tree.TreeNode;

public class RangeSumOfBst {
    public static void main(String[] args) {
        Solution solution = new RangeSumOfBst().new Solution();
    }
        //leetcode submit region begin(Prohibit modification and deletion)
/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode() {}
 *     TreeNode(int val) { this.val = val; }
 *     TreeNode(int val, TreeNode left, TreeNode right) {
 *         this.val = val;
 *         this.left = left;
 *         this.right = right;
 *     }
 * }
 */
class Solution {
//    int ans = 0;
    public int rangeSumBST(TreeNode root, int low, int high) {
        if(root == null) return 0;
        if(root.val <= high && root.val >= low){
            return rangeSumBST(root.left, low, high) + root.val + rangeSumBST(root.right, low, high);
        }else if(root.val < low){
            return rangeSumBST(root.right, low, high);
        }else{
            return rangeSumBST(root.left, low, high);
        }
    }
}
//leetcode submit region end(Prohibit modification and deletion)

}